Thursday, 6 August 2015

Group selection and WD Hamilton

WD Hamilton, one of the deepest thinkers on evolutionary theory, himself believed in group selection - this comes up repeatedly throughout his Narrow Roads of Gene Land. And this is a fact which people need to recognize and take seriously.

I was trained-up in the 'group selection does not exist'/ selfish gene school of Dawkins - and the Selfish Gene was a clear explanation of some insights from GC Williams and WD Hamilton. I arrogantly regarded all group selection explanations as naive and superficial - I saw the task of modern evolutionary theory as being to find the true selfish gene mechanisms to explain all apparent instances of group selection.

It was only when I read Hamilton's Narrow Roads, that I began gradually to realize that Dawkins, and mainstream evolutionary theory, has been highly selective and indeed deceptive in its advocacy of Hamilton's work - simply taking what it liked, and rejecting what it didn't.

So belatedly, and much influenced by Michael A Woodley, I came around to acknowledging the validity of group selection - even when we are unsure of its mechanism.

After all, there is a mass of prima facie evidence of group selection! For more than a century, group selection was accepted by everybody (including people much smarter than ourselves) as the obvious explanation for many phenomena.

Why should we always assume that group selection can be, must be, an illusion that should be explained-away by selfish gene mechanisms? There is no good reason.

If we accept the validity of some of Hamilton's selfish gene work, then it is reasonable to accept the validity of his other work in which he used group selection explanations.

Group selection should not be regarded as an explanation of last resort, used only when all possible selfish gene selection explanations have been eliminated - but as a mechanism which is relevant in some situations, and not in others. the proper question to ask is what is the most plausible selective explanation for a given situation under consideration - sometimes this will be a group mechanism, other times not

The task is not to deny group selection, but to discover the mechanisms by which it works - by which adaptive genetic change can result from selection of the group. This is, in microcosm, a version of one of the main problems of evolutionary theory - which is how high level cooperation is maintained in the face of lower level selection mechanisms which tend to dismantle it.

(see The major Transitions of Life by Smith and Szathmary - 1995 - for an account of the multi-level problem -

https://en.wikipedia.org/wiki/The_Major_Transitions_in_Evolution ):

One example is that natural selection within the body tends to produce neoplasms, such as cancers; thereby undoing the adaptations which enable the existence of multicellular organisms with specialized and cooperative cells. It is a problem to understand how multi-cellularity evolved when neoplasms were continually being produced.

That is what is lacking at present - one or more simple, comprehensible physiological and molecular mechanisms that enable group selection. There seem to be inklings of this in the literature, but the whole thing has not yet crystallized.

My hunch is that there is some kind of active/ purposive mechanism or process involved, or more than one such mechanism/ process - which is aimed-at higher organization and cooperation, and which under some circumstances can overcome the well-understood tendency to dis-integration.

12 comments:

Bruce B.
said...

Is group selection what Frank Salter is describing in his work on ethnic genetic interests? I follow some of the HDB blogs where Salter’s work is referenced but I don’t really understand genetics at all.

I am curious. What is the response from your colleagues when you present ideas like this? Or don't you? They must also know you are a serious Christian. Do they give you a hard time or are they respectful of your beliefs? I understand if you don't wish to comment on it publicly.

@ads - Maybe you meant to put this comment somewhere else? But if you mean this post, nobody is really interested in ideas like this - least of all professional biologists. Having done so with this kind of thing in the past, I'm afraid I cannot any longer be bothered to publish.

Dawkins has a slightly more sophisticated position than presented (you must have read The Extended Phenotype at some point). Gene centric but he's quite happy (insists actually) to look beyond the individual organism. Why multicellular organisms exist at all concerns him greatly.

@RP - Indeed, but the branch of evolutionary theory I used to inhabit derived from the decisive publication of The Selfish Gene, which I read as a school kid on publication, and the view of groups selection was as described. I think Dawkins personally - through most of his career anyway - regarded group selection as theoretically possible, but in practice extremely unlikely. My point here is that he, and many others in Evolutionary Biology, profess to revere Hamilton, but leave out the bits of Hamilton the do not like, but without engaging with him/ them - in this I think they probably felt they were doing him a favour (forgiving him and 'covering up' his embarrassing manias and eccentricities, such as a lifelong interest in matters related to eugenics/ dysgenics).

I guess what I am wondering is if your colleagues are hostile to your Christianity or just ignore it, pretend it doesn't exist? I only ask because I went to a Jesuit institution (I was an atheist at the time) and the university was completely at odds with itself but, no one ever addressed this. It was totally ignored which, I found very strange but, no one else seemed to mind.

There must be an irony in Ed O. Wilson's story of how he read Hamilton's seminal paper while on a train journey to Florida during the '60s. He described his hostility (being a group selection adherent) to Hamilton's inclusive fitness concept yet by the time he arrived at his destination he had become a convert. (Shades of the Lewis bus trip.) Now of course, he has come full circle and returned to group selection at least concerning his beloved ants. However, it appears he misunderstood Hamilton in the first place.

I think the error we made was to assume that because some, perhaps many, examples of what looked like group selection could be explained more easily by kin selection - then this meant that *all* examples of group selection could be explained by kin selection or some other individual-level selection such as reciprocity.

It was not really that group selection explanations were 'refuted', but that in some specific instances the group selection explanation could be replaced by a simpler and more power explanation.

Bruce, what is an example of group selection that doesn't seem to have a "selfish gene" explanation? This whole conversation seems entirely abstract to me without knowing what such a thing might look like.

So, you are proposing that teleology may have a role in group selection, or in how multicellular organisms came to exist without individual cells selfishly mucking up the works? Is this related to Sheldrake's morphogenetic fields? If teleology comes into play, is God the most likely source, or are there other possibilities?

@Jonathan - I have a post half written on this topic which I am trying to clarify - but I think you have put your finger on it with that word Teleology. The main biological problem that needs explaining is higher forms of organization (eg multicellular organisms compared with single cell, social organisms compared with solitary). So, there needs to be an overarching purpose in order to organize the lower level, which in this instance is survival and reproduction of the higher level.

I see this all through biology, including the origins of life. The problem has never been solved and has indeed barely been addressed in the mainstream - although it is the same problem which has been discussed by 'mathematical' theoretical biologists interested in chaos, complexity, and fields - Goethe, D'Arcy Thomson, Waddington, Kauffman, Sheldrake. The difficulty is that they see the problem and propose specific 'solutions; at a very high level of generality and in a way which (I believe) is metaphysical rather than scientific, but without acknowledging the fact. Therefore they have proved very difficult to operationalize.

Perhaps the most convincing way to be more specific is to regard lower order entities (interacting systems of RNA molecules, of cells, or individual animals) as cooperating to perform *cognitive* processes - so that they have the ability to model the future, and forsee the consequences - therefore can suppress selfishness and enforce group-ishness. But that is perhaps just kicking the problem further down the street - because we need to know why these systems hang together and interact, what keeps this activity going.

Anyway, I take the option of saying that we can detect group selection at work, as the most plausible process, but leave aside the specifics of exactly how it is working. In other words it is important to recognize that it can exist, and the circumstances; but we can then stop at that point.

At present mainstream biology is in the position of saying that we don't believe in group selection 'because' we don't understand how it could work - which doesn't make much sense.

Of course, the vast majority of 'biologists' (more than 99 percent) are only concerned with careers, publishing, grants etc. and this kind of 'understanding' stuff is of sub-zero interest, and they feel no urge or need ever to think about it. So it is something pursued by amateurs of biology, out of simple curiosity.